Replacement of the front and rear brake pads. 1) - Disconnect: the wear sensor the parking brake cable (Fig. A)
Fig. A 1 - Seeger circlip 2) - Remove the outer dust cap protecting the guide bush (Fig. B). 3) - Remove the bolt (Fig. C) securing the guide bush to the brake calliper body. This procedure is required in order to rotate the brake calliper carrier clear of the calliper body (Fig. F / G).
4) - Using a suitable levering tool, carefully push back the guide bush into the brake calliper body (Fig. D). If necessary, gently tap the carrier with a soft faced hammer (Fig. E) to release the calliper carrier from the calliper body.
Do not use any oil, mineral grease, petroleum or paraffin (hydrocarbons), solvents or products which could attack the rubbers in the brake callipers.
5) - Rotate the brake calliper carrier up or down around the other guide bush (Fig. F / G).
Do not remove the guide bush. Do not smear the bushes or their seats with grease that is not specially designed for this purpose.
Fig. F Brake calliper, front brake
Fig. G Brake calliper, rear brake
6) - Remove the two worn brake pads from the brake calliper body. 7) - Retract the brake pistons back into their seats using the special tools designed for this job to ensure that the pistons are retracted square into their bores and to avoid damage to the piston surfaces and gaiters. Retracting the pistons will raise the level of the brake fluid in the reservoir, check that the fluid does not spill out and damage the vehicle paint work.
Do not damage the dust gaiter seals because that could lead to: Premature brake pad wear. Irregular wear between the brake pad on the piston side and the brake pad on the reaction side. 8) - Allow any air trapped under the brake piston dust gaiter to escape (Fig. H).
Do not damage the dust seals. If damaged, replace: only the dust seals of the front and rear brake callipers on models 40C ÷ 65C, by using the seals from the kit from the Parts Department. the complete rear brake calliper on models 29L ÷ 35C.
Fig. H 9) - On brake calliper versions with springs on the sides as shown in Fig. L, the springs must be replaced by springs from the kit with the seats previously cleaned. If the brake callipers however have a central spring, as shown in Fig. M, this spring must not be replaced and also must not removed from its seat.
Ensure that the springs are fitted correctly to prevent deformation.
10) - Clean the brake pad contact surfaces of the calliper body using suitable materials and products then fit the new brake pads.
If there are arrows on the brake pads, as shown in Fig. N, these must point towards the rotation of the brake disc.
Fig. N Secure the brake pad wear sensor to the brake pad with the furthest protruding side of the sensor ("sonde") pointing towards the side of the brake pad friction face (Fig. P). The brake pad with wear sensor must be fitted in the position described in the Workshop Manual.
Fig. P Correct connection
Fig. Q Improper connection
11) - Insert the wear sensor connector through the spring hole or through the hole in the brake calliper body and allow it to project through the outside of the brake calliper. 12) - Carefully clean the seat and the end of the guide bush using suitable materials and products. 13) - Rotate the brake calliper carrier back into position around the fitted guide bush and secure the other bush in its seat in the brake calliper body without damaging the dust seals. 14) - Replace the bolts removed earlier and tighten the new bolts to a torque setting of 28
÷32 Nm (fig. R).
Fig. R 15) - Refit the dust caps removed earlier and pay attention to the following: Carefully clean the dust cap seats in the brake calliper. Rotate the dust caps around in the brake calliper to ensure that they engage correctly in their seats. If the dust caps removed earlier are damaged, these must be replaced with dust caps from the relevant kit. 16) - Reconnect the wear sensor. 17) - Refit the parking brake cable on the mounting bracket and secure with the Seeger circlip (Fig. A). 18) - Run the pads in avoiding braking at high speeds for the first 100 km. To be avoided: The brake calliper must not be exposed to shocks. Avoid contact of the rubber dust caps, dust gaiter seals and dust covers with sharp metal tools. Damaged components mean correct sealing can no longer be guaranteed causing the ingress of water and contaminates. This leads to oxidation, resulting in binding of moving parts. Do not use unsuitable oils and greases which attack the sealing properties allowing the ingress of water and contaminates with resulting binding of moving parts (use, if necessary, "SYNTHESO GLK 1PF" grease from "KLÜBER"). Do not soil the brake pads with fluids or grease. A differing friction coefficient between the two brake pads can cause irregular wear.